Medical treatment in pregnant women with subclinical hypothyroidism: systematic review and meta-analysis

Abstract Objectives: to determine the effectiveness of medical therapy in reducing complications associated with subclinical hypothyroidism during pregnancy. Methods: in 2021, a systematic review of available cohort studies was carried out in three databases, with no publication date limit. Study selection and data extraction were performed in duplicate. Random-effects meta-analysis was performed, and odds ratios were calculated, with the corresponding 95% confidence intervals. Cohort risk of bias was assessed using the Newcastle-Ottawa Scale (NOS). The certainty of the evidence was assessed using the GRADE methodology. Results: five studies were included for qualitative and quantitative synthesis. A statistically significant relationship was found between medical treatment in pregnant women with subclinical hypothyroidism with respect to spontaneous abortion (p=0.03; OR=0.77; CI95%=0.61-0.97), and no statistically significant relationship was found for delivery preterm (p=0.46; OR=1.11; CI95%=0.85-1.44), nor for abrupt placentae (p=0.56; OR=1.60; CI95%=0.33-7.66). Three studies were at moderate risk of bias, and two were at low risk of bias. In all the results the certainty was very low. Conclusions: medical treatment of subclinical hypothyroidism during pregnancy can have a beneficial effect in reducing cases of spontaneous abortion.

摘要 研究目的：明确药物治疗对降低妊娠期间亚临床甲状腺功能减退症（subclinical hypothyroidism）相关并发症的有效性。
方法：2021年，在三个数据库中针对已发表的队列研究开展系统综述（systematic review），未设置发表日期限制。研究筛选与数据提取工作均由两名研究者独立重复完成。采用随机效应模型开展Meta分析，计算比值比（odds ratios, OR）及其对应的95%置信区间（confidence intervals, CI）。采用纽卡斯尔-渥太华量表（Newcastle-Ottawa Scale, NOS）评估队列研究的偏倚风险。采用GRADE（分级推荐、评估、发展与评价）方法评估证据确定性。
结果：共纳入5项研究进行定性与定量综合分析。针对妊娠亚临床甲状腺功能减退症患者的药物治疗与自发性流产的相关性具有统计学意义（p=0.03；OR=0.77；95%CI=0.61~0.97）；其与早产分娩（p=0.46；OR=1.11；95%CI=0.85~1.44）、胎盘早剥（abrupt placentae）的相关性均无统计学意义。3项研究存在中等偏倚风险，2项研究偏倚风险较低。所有研究结果的证据确定性均为极低等级。
结论：妊娠期间亚临床甲状腺功能减退症的药物治疗，可在降低自发性流产发生率方面产生有益效果。